Stream Deck button showing alert icon when I attempt to map to a trigger in KM

Hello, I'm new to KM and want to trigger a macro with my Stream Deck (software v4.9.2 (13193) on macOS 10.15.7. I am following the MacSparky KM Field Guide tutorial on how to do this but am running into a problem. When I attempt to assign the USB Device Key Trigger, KM shows text that reads "Press and Release"...at this time I press the Stream Deck button. Instead of the mapping reflecting in KM, nothing happens in KM but on the Stream Deck I see a yellow alert icon. I'm at a loss for what I'm doing wrong. Any guidance would be greatly appreciated.

Thanks!

Ben